Electric-arc mechanism for searchlights



L. C. JOSEPHS, JR. ELECTRIC ARC MECHANISM FOR SEARCHLIGHTS.

APPLICATION FILED IUNEQ, 1919. I

Patented Oct. 3, 1922.

HEETS-SHEET I.

avwmdoz gim zgw L. C. JOSEPHS, JR. ELECTRIC ARC MECHANISM FOR SEARCHLIGHTS.-

APPLICATION FILED JUNE 9,1919.

Patented Oct. 3, 1922.

2 SHEETS-SH EET 2.

Patented Oct. 3, 1922.

UNITED STATES PATENT OFFICE,

LYMAN, c. JOSEPHS, .73., or THE UNITED STATES ARMY, ASSIGNOR To NEWTON'ID.

. BAKER, SECRETARY oF'wAR, TRUSTEE.

ELECTRIC-ARC MECHAN ISM FOR SEARC HLIGHTS.

Application filed June 9, 1919; Serial No. 302,979.

(FILED, UNDER THE ACT or mmcm a, 1883,. 22.STAT. L., 625.

To all whom it may concern:

Be it known that I, LYMAN C. JOSEPHS,,J

an ofiicer of the United States Army,a 'citie zen of the United States, and a resident of Flushing, in thecounty of'Queens and State of New York, have invented an Improvementin Electric-Arc Mechanism for- Searchlights, of which the following is a specification.

used by the. Government, or any of its officers or employees in prosecution of work forthe Government, or by any other person in the United States without payment of any royaltythereon. r

y invention relatesto; electric arcmechanisms for light projectors or searchlights and has for its object to provide an improved, form of mechanism for controlling-the operation and burning of an electric arc.

In my co-pending patent application, Serial Number 302.313, filed June 5, 1919-, there issh'own and. described a hand operatedarc mechanismfor open type searchlights in which rotation and feeding of the positive carbon is obtained by turning ahandle, and feeding of the negative carbons is obtained by pushing a handle. It has been found that with such a mechanism,the operator ls liable either to fail to rotate. the positive carbon enough to keep a good crater or to move the negative carbon too far, thus disturbing the burning of the arc.

By my present invention, I provide an improved form of hand operated electric arc mechanism, of the above described type,

in which the movement-of the negative carbon is so limited as to prevent abrupt changes in the arc. length. By my invention, I also provide novel means forcontrolling the burning of the arc flame, so that it is not necessary to rotate the positivecarbon.

In the accompanying drawings; Fig. 1 is a general perspective view of an arc mechanism embodying my invention.

Fig. 2 is a view partially in section and partiallyin side elevation of-the mechanism shown in Fig. 1.

. Fig. 3 is a transverse'sectional view along the line 33 of Fig. 2. j

Fig. 4: is detail of a portion ofthemechanismshown in Fig. 3.

Fig. 5 is an enlarged view showing details of the negative head. i

ing? that extends through a central opening 3 in a mirror 4. A ring 5 is supported at one end of the casing 1 by ribs 6 to which are secured. a plurality of ribs 7, which serve to The invention described herein may be.

support an arc casing 8 at their outer ends. A tube 9 is centrally supported within theic'asingl'by means of end'plates 10 andll,

which are preferably composed of insulating isprovided with a central. opening 16 within which are pivotally mounted; cam contact members 17. The contaet'members 17 are normally held in engagement with a negathe feed'tube 18 by means ofsprings 19. i

As the cam contacts 17 are normally held in frictional engagement with the tube 18, longitudinal actuation of the latter is prevented unless accompanied by a turning movement. Rotatingthe tube 18 tends to depress cam contacts 17, thus diminishing their pressure-upon the surface of the tube, sufficiently to permit its actuation toward the opposing carbon.

The tube 18 extends through the plate 15 and is provided at one end with a shoulder 20. The portion of the'tiube- 18 within the casing 9 is provided with an enlarged portion 21, and 'asecond reduced portion 22 which is provided at its end with a handle 23. The reduced portion 22 is supported at point adjacent to the enlarged portion 21 by means of an insulating bushing 24, through which the portion 22 is adapted to be moved by means of the handle 23. An arcstriker rod 25extends through the tube 18 and is spaced therefrom by means of bushings 26v and 27. The .rod 25 is provided at one end with a chuck type carbon holder 28. The carbon holder 28 comprisesa threaded portion 29, a sleeve 30 coacting therewith and a tapered socket 31 that extends through the tube 22 and is provided at its end with a handle 35. The reduced portion 34 is supported in a bushing 36 that is carried by an end plate 37 of the portion 21. The other end of the enlarged portion 21 is provided with an end plate 38 and a spiral spring 39 surrounds the rod between the end plate 38 and the shoulder 33 and tends to maintain the shoulder 33 against the end plate 37. In order to strike the arc, the handle is pushed in to move the negative carbon forward and the spring 39 returns the negative carbon 32* to its original position as soon as the handle 35 is released.

A positive carbon 40 extends through a head 41 that is supported within the cylindrical casing 8. The carbon 40 is surrounded at its end by a tip 42 and a shield 43, both of which are secured to the head 41 by bolts 44 and insulating Washers 45' and 46. The tip 42 and shield 43 are preferably composed of material having relatively high heat conductivity for the purposes set forth in my copending patentapplication, Serial Number 302,980, filed June 9, 1919.

Current is conducted to the positive car bon 40 by means of brushes 47 that pass through the head 41 and are held in engagement with the positive carbon 40 by pivoted arms 48 and springs 49. The end plate 10 is provided with a socket 50 that is electrically connected to a collector ring 51 by means of conductor 52. A bus bar 53 is supported by an arm 54 that is mounted on the end plate 15 of the tube 9 and is separated therefrom by insulating washer 55. The bus bar 53 is electrically connected at one end to the collector ring 51 by means of a spring pressed brush 56 and is electrically connected at its other end to the casing 8 by means of a brush 57 that is in engagement with a ring 58 carried by the casing 8. Current is thus conducted from the socket 50 to the positive carbon 40 along a path that is substantially parallel to the longitudinal axis of the positive carbon 40.

The positive carbon 40 is adapted to be moved longitudinally by means of a roller 59 that is carried by shaft 60 pivotally mounted on the casing 8. The shaft 60 is further provided with a star wheel 61, the teeth of which are adapted to be engaged by an arm 62 carried by the bus bar 53. as best shown in Figs. 3 and 4. When the tube 9 is rotated by means of a handle 63, the bus bar 53 is carried around with it and the arm 62 engages the star wheel 61 once for each revolution of the tube 9, thus turning the feed roller 59. When the arc is burning, the magnetic field surrounding the bus bar 53 causes the arc flame to be deflected away from the bus bar 53. Consequently. when the bus bar 53 is rotated about the carbons 32 and 40, it causes the are flame to rotate with it, which results in the formation of a symmetrical crater at the end of the positive carbon 40 in the same manner as a crater is produced by actual rotation of the positive carbon. Thus it may be seen that by turning the handle 63, the positive carbon 40 may be fed forward and at the same time the arc flame rotated to form a good crater. The heated products of combustion from the arc flame pass between the shield 43 and the casin 8 and from thence pass outwardly throug openings 64 in the head 41 and openings 65 in the hood 66.

I claim as my invention:

1. In an electric arc mechanism, the combination with positive and negative carbons, a feed roller for moving said positive carbon and a bus bar for conducting current to said positive carbon in a direction parallel to the axis of said carbon, of means for moving said bus bar about the said positive carbon to cause rotation of the flame between said carbons and turning of said feed roller.

2. In an electric arc mechanism the combination with positive and negative carbons, a feed roller for moving said positive carbon and a bus bar for conducting current to said positive carbon in a direction parallel to the axis of said carbon, of means connecting said bus bar to said feed roller whereby rotation of said bus bar about the axis of said positive carbon causes simultaneous rotation of the arc flame and movement of said positive carbon.

3. In an electric arc mechanism the combination with a positive and negative carbon including means for conducting current to one of said carbons in a path substantially parallel to its axis; of a mechanism for feeding the positive carbon and simultaneously revolving the path of the current about an axis coincident with that of said carbons, to produce rotation of the arc flame.

4. In an electric arc mechanism the combination with a positive and negative carbon including means for conducting current to one of said carbons in a path substantially parallel to its axis; of a mechanism for advancing the positive carbon and simultaneously revolving the path of the current about an axis coincident with said carbons, to produce rotation of the arc flame.

5. An electric arc mechanism, comprising a tubular member, means for rotatably and slidably mounting said member, oppositely located depressible cams frictionally engaging the tubular member. said cams normally functioning to prevent actuation of said member until depressed by its rotary movement, a carbon holder carried by the free end of said member and normally movable therewith, and means co-operating with said holder to effect its independent movement with respect to the tubular member for the purpose of striking an are. r

6. An electrical arc mechanism comprising a guiding element, a tubular member, means for rotatably and slidably actuating such tubular member through said guiding element, oppositely located depressible cams mounted in the guiding element and fric- 10 tionally engaging the tubular member, said cams functioning to prevent longitudinal actuation of said member until depressed by its rotary movement, a carbon holder carried by the free end of said member and movably therewith and means co-operating with said holder to effect its independent movement with respect to the tubular member for the purpose of striking an arc.

LYMAN o. JOSEPHS, JR. 

